Mems package structure and method for manufacturing same

Abstract

A MEMS package structure and a method for manufacturing same. The MEMS package structure comprises a MEMS die (200) and a device wafer (100). The MEMS die (200) has micro-cavities (211, 221) and contact pads (212, 222) configured to be coupled to an external electrical signal. The micro-cavity (221) of the MEMS die (200) has an opening (221a) in communication with the outside. The device wafer (100) is provided therein with a control unit corresponding to the MEMS die (200). An interconnection structure (300) is provided in the device wafer (100) and is electrically connected to each of the contact pads (212, 222) and the control unit. A rewiring layer (400) electrically connected to the interconnection structure (300) is provided on a second surface of the device wafer (100). The provision of the MEMS die (200) and the rewiring layer (400) respectively on both sides of the device wafer is conductive to reducing the size of the MEMS package structure; various MEMS dies can be integrated on one device wafer, thereby meeting the requirements for the function integration capability of the MEMS package structure in practical application.

What is claimed is: 
     
         1 . A micro-electro-mechanical system (MEMS) package structure, comprising:
 a MEMS die comprising a micro-cavity and a contact pad configured to be coupled to an external electrical signal, wherein the micro-cavity of the MEMS die has an opening in communication with an outside;   a device wafer having a first surface and a second surface opposite to the first surface, wherein the MEMS die is bonded to the first surface, and wherein a control unit associated with the MEMS die is arranged in the device wafer;   an interconnection structure arranged in the device wafer, wherein the interconnection structure is electrically connected to each of the contact pad and the control unit; and   a rewiring layer arranged on the second surface, wherein the rewiring layer is electrically connected to the interconnection structure.   
     
     
         2 . The MEMS package structure of  claim 1 , wherein a plurality of MEMS dies are bonded to the first surface, and wherein the plurality of MEMS dies are categorized in a same or different types depending on a fabrication process thereof. 
     
     
         3 . The MEMS package structure of  claim 1 , wherein a plurality of MEMS dies are bonded to the first surface, and wherein each of the plurality of MEMS dies has the opening in communication with the outside, or at least one of the plurality of MEMES dies is provided with a closed micro-cavity. 
     
     
         4 . The MEMS package structure of  claim 3 , wherein the closed micro-cavity is filled with a damping gas or is vacuumed. 
     
     
         5 . The MEMS package structure of  claim 1 , wherein a plurality of MEMS dies are bonded to the first surface, and wherein the plurality of MEMS dies include at least two of: a gyroscope, an accelerometer, an inertial sensor, a pressure sensor, a displacement sensor, a humidity sensor, an optical sensor, a gas sensor, a catalytic sensor, a microwave filter, a DNA amplification microchip, a MEMS microphone and a micro-actuator. 
     
     
         6 . The MEMS package structure of  claim 1 , wherein the control unit comprises one or more MOS transistors. 
     
     
         7 . The MEMS package structure of  claim 6 , wherein the interconnection structure comprises
 a first conductive plug and a second conductive plug, wherein: the first conductive plug extends through at least a part of the device wafer and is electrically connected to the control unit; and the second conductive plug extends through the device wafer and is electrically connected to the contact pad, and wherein the rewiring layer is electrically connected to each of the first and second conductive plugs.   
     
     
         8 . The MEMS package structure of  claim 7 , wherein an isolation structure is arranged in the device wafer and located between adjacent MOS transistors, and wherein each of the first and second conductive plugs extends through the corresponding isolation structure. 
     
     
         9 . The MEMS package structure of  claim 1 , further comprising:
 a bonding layer covering the first surface, wherein the MEMS die is bonded to the first surface by the bonding layer; and   an encapsulation layer covering the MEMS die and the bonding layer, and exposing the opening in communication with a corresponding micro cavity with the outside.   
     
     
         10 . The MEMS package structure of  claim 9 , wherein the bonding layer comprises an adhesive material. 
     
     
         11 . The MEMS package structure of  claim 10 , wherein the adhesive material comprises a dry film. 
     
     
         12 . The MEMS package structure of  claim 1 , wherein the contact pad is located on a surface opposite to the first surface, and wherein the opening of the micro-cavity which is in communication with the outside faces a direction away from the first surface. 
     
     
         13 . The MEMS package structure of  claim 1 , wherein the rewiring layer comprises a rewiring connection, and wherein a solder pad is electrically connected to the rewiring connection. 
     
     
         14 . A method for fabricating a micro-electro-mechanical system (MEMS) package structure, comprising:
 providing a MEMS die and a device wafer for control of the MEMS die, wherein: the MEMS die comprises a micro-cavity and a contact pad configured to be coupled to an external electrical signal; the micro-cavity of the MEMS die has an opening in communication with an outside; the device wafer has a first surface; and a control unit is formed in the device wafer;   bonding the MEMS die to the first surface;   forming an interconnection structure in the device wafer, wherein the interconnection structure is electrically connected to each of the contact pad and the control unit; and   forming a rewiring layer on a surface of the device wafer opposing the first surface, wherein the rewiring layer is electrically connected to the interconnection structure.   
     
     
         15 . The method for fabricating a MEMS package structure of  claim 14 , wherein bonding the MEMS die to the first surface comprises:
 forming a bonding layer to bond the MEMS die to the first surface;   forming a sacrificial layer to cover the opening; and   forming an encapsulation layer to cover the MEMS die and the bonding layer, and to expose the sacrificial layer.   
     
     
         16 . The method for fabricating a MEMS package structure of  claim 15 , further comprising, subsequent to the formation of the rewiring layer, removing the sacrificial layer to expose the opening. 
     
     
         17 . The method for fabricating a MEMS package structure of  claim 14 , wherein forming the interconnection structure in the device wafer comprises:
 forming a first conductive plug and a second conductive plug in the device wafer, wherein: the first conductive plug extends through at least a part of the device wafer and comes into electrical connection with the control unit; and the second conductive plug extends through the device wafer and comes into electrical connection with the contact pad, and wherein each of the first and second conductive plugs has one end exposed at the surface of the device wafer opposing the first surface.   
     
     
         18 . The method for fabricating a MEMS package structure of  claim 14 , further comprising, prior to the formation of the interconnection structure in the device wafer,
 grinding the device wafer along a thickness direction of the device wafer from a side of the device wafer opposing the first surface.